ANTH151 Lecture Notes - Lecture 2: Transitional Fossil, Teleology, Uniformitarianism
10 May 2018
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ANTH151 Lecture
II: Natural Selection and Genetics
Darwin’s predecessors
• Linnaeus
• Carl von Linne
• Swedish classifier of species
• Highlighted their similarities
• Buffon
• George-Louis Leclerc, Comte du Buffon - against idea of stable, perfect creation
• Imperfections in organisms
• Erasmus Darwin
• Erasmus Darwin - Divine creation, but process of speciation
• Natural theology approach
• Lamarck
• Jean Baptiste Pierre Antoine de Monte, Chevalier de Lamarck - species change for
environment
• Will to change; inheritance; and law of use and disuse
• Focused on adaptation
• James Hutton and Charles Lyell
• James Hutton and Charles Lyell - geological uniformitarianism
• Suggested earth was very old (deep time)
Darwin’s context
• Contemporaries considering species change
• Sense of time depth growing due to geology
• Most theorists, however, believed in degeneration (post Lapsarian) aspirational change, or
catastrophism
• Many proposals of evolution, but none were compelling until Darwin’s
Charles Darwin before the beagle
• Born 1809
• Established, well-to-do family (father a doctor)
• Failed as doctor, indifferent clergy student
• Loved hunting, collecting, beetles
• Replaced a last minute absence
• Father opposed voyage
• On board kept captain company
• More interested in geology than biology
Charles Darwin on the beagle
• 90’ long
• Carried 74 people
Darwin in Australia
• Stopped 3 times in Australia (Jan-Mar 1836)
Key dimensions of Darwin’s thoughts
• Species change (Darwin found bones of related, but distinct, earlier forms)
• Population ever increasing (Malthus), so survival not guaranteed (evidence of extinct
animals)
• Species varied from place to place (islands with isolated species)
• Variation emerged; species had deep relations and shared origins
find more resources at oneclass.com
find more resources at oneclass.com
Theorising about natural selection
• Darwin returned with beagle in 1836
• William Wells had described natural selection in 1818; Patrick Matthew in 1831
• In 1844, Darwin wrote book but held it in secret (to be published if he died). His ideas
emerged early in notebooks
• In 1858, after 20 years writing about biology, Darwin received package from Alfred Russel
Wallace
Wallace-Darwin
• 1 July 1858, at the Linnaean Society in London - Wallace’s very clear statement of principles
of evolution read out with part of Darwin’s unpublished 1844 manuscript and an 1857 letter
• Rocked the scientific world to its foundations
The origins of species (Charles Darwin)
• 1859
• Best-seller that went through 6 editions in his life
• Staggering breadth: finches, pigeons, cavefish, gooseberries, honeybees…
• Piling up of evidence is overwhelming
• Suddenly, instead of description, we have also explanation
Darwin’s intellectual legacy
• Darwin died renowned for ‘evolution’ - he was uncomfortable with the term, preferred
‘transmutation’
• Natural selection not widely accepted, even by Darwin’s supporters - by 1875, largely
neglected by biologists
• A reluctant revolutionary - natural selection ‘like confessions a murder’
• Worried about religion, social respectability, even about hurting his wife, Emma, who
worried for his soul
• Changed the shape and tenor of biology
• Placed human among other animal species for study
• Suggested that species did not have ‘essence’; instead dynamic populations with inherent,
constant variation, liable to speciation or change over time
• ‘Evolution’ was not a result of design, striving or effort
Natural selection
• Variation + inheritance + selection + time = adaptation
• Species have significant heritable variation
• More individuals are born than can survive to reproduce
• Variation affects reproductive success
• Overtime, species adapt to ecological niches
Patterns of selection
• How fast is evolution?
• Darwin tended to focus on gradual change, and long periods of similar fossils
supported this vision
• But moments in fossil record where pace accelerates
• No inherent reason pace of evolution needs to be consistent if environment was not
(and environment includes animals)
• Punctuated equilibrium
• Examples of rapid change
• Queensland frog-eating snakes
• Antibiotic resistant bacteria
• Understanding punctuated equilibrium
• Important: ‘selection’ always occurring
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Darwin"s predecessors: linnaeus, carl von linne, swedish classifier of species, highlighted their similarities, buffon, george-louis leclerc, comte du buffon - against idea of stable, perfect creation. Imperfections in organisms: erasmus darwin, erasmus darwin - divine creation, but process of speciation, natural theology approach, lamarck. Jean baptiste pierre antoine de monte, chevalier de lamarck - species change for environment: will to change; inheritance; and law of use and disuse, focused on adaptation. James hutton and charles lyell - geological uniformitarianism: suggested earth was very old (deep time) Darwin"s context: contemporaries considering species change, sense of time depth growing due to geology, most theorists, however, believed in degeneration (post lapsarian) aspirational change, or catastrophism, many proposals of evolution, but none were compelling until darwin"s. Charles darwin on the beagle: 90" long, carried 74 people. Darwin in australia: stopped 3 times in australia (jan-mar 1836)
